1. Technical Field
The present invention relates to high-frequency heating devices, semiconductor manufacturing devices, light source devices, and more specifically, to those suitably used with a method of microwave generation using a solid-state oscillator.
2. Related Art
With related-art high-frequency heating devices, substances such as food are heated utilizing the vibration of water molecules at the time of microwave irradiation. Semiconductor manufacturing devices generate plasmas utilizing pumping and ionization of gas at the time of microwave irradiation.
For generation of microwaves, a kind of vacuum tube such as a magnetron oscillator (hereinafter, magnetron) or klystron oscillator is widely used since each is capable of efficiently generating a high-frequency output.
Using the magnetron in a heating device, for example, however, causes a frequency fluctuation problem in that intermittent microwave operation and a load-fluctuating heating object cause the oscillation frequency to fluctuate due to reflected wave returning to an oscillator tube, a useful life problem of making a filament unavailable due to wire breakage, an unwanted emission problem in that due to unwanted emission from the magnetron, the interference wave make radio communications equipment such as Bluetooth and WLAN used in an ISM band unavailable for communications, and other problems as well.
Such problems are observed not only in heating devices but also in radar equipment, medical equipment, semiconductor manufacturing devices, and other microwave application equipment using a magnetron. To solve such problems, for example, JP-A-3-194893 and JP-A-2002-246167 disclose a device with a solid-state high-frequency oscillator that does not use a magnetron of a vacuum tube type.
The issue here is that the solid-state high-frequency oscillators disclosed in JP-A-3-194893 and JP-A-2002-246167 merely amplify a high frequency coming from the oscillator using an amplifier configured by a transistor, and no specific method of generating a high frequency microwave band is disclosed.